Daktronics AB-1600-1.5,2.5 - Manual (Page 33)

Electrical Installation
3-7
Branch Circuit Grounding
A grounding electrode at separate structures/displays shall not be required where only one
branch circuit supplies the structure and the branch circuit includes an equipment-grounding
conductor for grounding the non-current-carrying parts of all equipment.
Power Installation
There are two considerations for power installation; installation with ground and neutral conductors
provided and installation with only a neutral conductor provided. These two power installations
differ slightly, as described in the following paragraphs:
Installation with Ground and Neutral Conductors Provided
For this type of installation, the power cable must contain an isolated earth-ground conductor.
Under this circumstance, do not connect neutral to ground at the disconnect or at the display.
This would violate electrical codes and void the warranty. Use a disconnect so that all hot lines
and neutral can be disconnected. Refer to Figure 28 for installation details. The National
Electrical Code requires the use of a lockable power disconnect within sight of or at the
display.
Installation with Only a Neutral Conductor Provided
Installations where no grounding conductor is provided must comply with article 250-
32 of the National Electrical Code. If the installation in question meets all of the
requirements of article 250-32, the following guidelines must be observed:
•
Connect the grounding electrode cable at the local disconnect, never at the display power
termination panel.
•
A disconnect that opens all of the ungrounded phase conductors should be used.
•
The neutral and the ground conductors should be bonded in the display power termination
panel.
Refer to Figure 29 for installation details.
Figure 28: Installation with Ground and Neutral Conductor Provided